Apparatus for selectively recycling used toner or delivering such toner to a container

ABSTRACT

An electrographic apparatus has a photoconductor on which a latent image is formed, and a development station provides particles of toner to the photoconductor for developing a latent image. After the developed image has been trnsferred to a copy sheet, residual toner particles remaining on the photoconductor are removed at a cleaning station. The removed toner particles are either returned to the development station of the electrographic apparatus for reuse or delivered to a container for disposal. For example, if a development station providing black toner particles to a photoconductor is replaced with a development station containing toner particles of a different color, the residual black toner particles removed at the cleaning station are delivered to the container in order to avoid contamination of colored tone particles in the development station with those black particles remaining on the photoconductor from the operation of the black development station operation.

BACKGROUND OF THE INVENTION

The present invention relates to electrographic apparatus wherein tonerparticles removed from a photoconductor during a cleaning operation canbe selectively returned to a development station for reuse or deliveredto a container for disposal.

During operation of known electrographic apparatus a latent image isformed on a photoconductor, a development station provides particles oftoner to the photoconductor for developing the latent image, and afterthe image is transferred to a copy sheet or the like, a cleaning stationremoves residual particles of used toner from the photoconductor. Insome instances the toner particles removed at the cleaning station arereturned to the development station for reuse. Apparatus for recyclingused toner is disclosed, for example, in U.S. Pat. Nos. 3,660,863,3,700,328, and 4,571,071, and in Item 17738 on page 37 of the January,1979 edition of Research Disclosure, published by Kenneth MasonPublications Ltd., The Old Harbourmaster's, 8 North Street, Emsworth,Hampshire, P010 7DD, England. In the beforementioned U.S. Pat. No.4,571,071, the recycling apparatus is disclosed for a color copier whichis capable of applying toners of four different colors from fourdevelopment stations to a photoconductor and recycling particles of eachcolor toner back to the respective development station.

It also is known to remove residual toner particles from aphotoconductor and deliver them to a container instead of recyclingthem. In this regard, see U.S. Pat. No. 4,082,061, for example. In thelatter patent residual particles of toners of three different colors areremoved from a photoconductor and delivered to three differentcollection bottles or containers.

In order to provide copies of a single color other than black,electrographic apparatus having a single development station thatnormally provides black toner particles to a photoconductor can bereplaced with a similar development station having toner particles of adifferent color, for example red, green, blue, brown, etc. Developerparticles of colors other than black can be used to print single colorimages on copy sheets, or can be used as an accent color on copy sheetson which black images also are produced during another run through theelectrographic apparatus. If the electrographic apparatus has a systemfor recycling previously used toner particles removed at the cleaningstation, then the recycling apparatus can contaminate the developmentstations by recycling some of the toner of one color (e.g. black) into adevelopment station containing toner of a different color (e.g. red). Atthe same time, since the electrographic apparatus probably will be usedprimarily for producing black images, it is desirable to continue torecycle used black toner particles to the development station duringlong runs when black toner is being used.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide electrographicapparatus with the advantages of a toner recycling system and also avoidcontamination of interchangeable development stations containing tonerparticles of different colors.

The present invention is usable with electrographic apparatus having aphotoconductor on which a latent image can be formed, and a developmentstation for providing particles of toner to the photoconductor fordeveloping the latent image. A cleaning station is provided for removingresidual particles of used toner from the photoconductor. Theimprovement of the invention comprises a container for receivingparticles of used toner from the cleaning station. A tube has a firstend portion connected to the development station and a second endportion connected to the container. Used toner particles from thecleaning station are provided to an intermediate portion of the tube. Anauger in the tube moves toner through the tube. Drive means coupled tothe auger rotates the auger in a first direction for returning usedtoner particles to the development station and for rotating the auger ina second direction for feeding used toner particles to the container.

BRIEF DESCRIPTION OF THE DRAWINGS

In the detailed description of the preferred embodiment of the inventionpresented below, reference is made to the accompanying drawings, inwhich:

FIG. 1 is a perspective view of electrographic apparatus incorporatingthe present invention; and

FIG. 2 is an enlarged detail cross section view of a portion of the FIG.1 apparatus.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to FIG. 1 of the drawings, a fragmentary portion of anelectrographic apparatus is generally designated 10 and may, forexample, comprise part of a copier/duplicator. The apparatus 10 has anendless photoconductor 12 that is trained about a plurality of rollers14, at least one of which is driven to move the photoconductor in agenerally counterclockwise direction as shown by the arrow in FIG. 1. Asknown in the electrographic arts, the photoconductor is moved past aplurality of stations at which latent images are formed on thephotoconductor, developed, transferred and fused to copy sheets. Thenthe photoconductor is cleaned and the cycle is repeated again. Onlythose stations related to the present invention are illustrated indetail in the drawings.

After a latent image is formed on the photoconductor, it is driven pasta development station generally shown at 16 where the latent image isdeveloped by developer material. More specifically, station 16 includesa housing 18 which holds developer material comprising, for example,carrier particles and toner particles. The developer mix is brought intocontact with, or adjacent to, the surface of the photoconductor so thatthe toner particles can be transferred to a latent image to develop theimage. Because some of the toner is thus depleted from the developmentstation 16, it is necessary to introduce a fresh supply of toner intothe station. This can be accomplished by means of a supply bottle orcontainer 20 which is connected to the left end of the station, asviewed in FIG. 1, such left end being the front of the developmentstation in the electrographic apparatus.

After the developed image has been transferred to a copy sheet forfusing the image thereto, some residual toner particles remain on thephotoconductor 12 and need to be removed therefrom prior to the nextcycle of operation in order to maintain high quality reproduction ofimages. The photoconductor is cleaned of residual toner particles in acleaning station generally designated 22. Station 22 includes agenerally cylindrical housing 24 enclosing a brush 26. The brush engagesthe photoconductor across its width and rotates in a direction oppositeto the direction of movement of the photoconductor through the cleaningstation to thereby clean the photoconductor of residual toner particles.

A vacuum hood 28 extends from the housing 24. A flexible conduit 30 hasone end portion connected to the hood 28 and the other end portion is incommunication with the inlet opening of a blower 32.

Upon operation of the blower suction is applied through the conduit 30and hood 28 to create a vacuum in the housing 24. The vacuum withdrawstoner particles removed from the photoconductor by the brush and movesthem through the conduit and toward the blower 32. In this manner thetoner particles are delivered to a cyclone separator 34 where the tonerand air mixture is spiraled around the separator and centrifugal forcepropels the toner particles to the outer wall of the separator.

As air is drawn out of the separator by the blower 32, the tonerparticles move downwardly into a tube 36 and pass through an airlock 38.The airlock is necessary in order to maintain vacuum in the separator.The airlock may comprise, for exmple, a pair of cam operated pinchvalves located in vertically spaced relation along the tube and operatedsequentially so that the top cam is moved to open the tube and allowtoner to drop past the first cam and then the first cam is closed andthe lower cam opens the tube to allow toner between the cams to pass thesecond cam and drop through the bottom of the tube. A cam operatedairlock of this type is disclosed in the beforementioned ResearchDisclosure publication item 17738. As explained in the ResearchDisclosure publication, the toner particles passing through the airlockcan be driven by an auger back to the development station 16 for use indeveloping other latent images on the photoconductor.

Referring now to FIG. 2 of the drawings, an elongate generallycylindrical tube 40 is located beneath the lower end of the tube 36.Tube 40 can be made in sections, as illustrated in the drawings, or froma single piece of tubing. Tube 40 has an elongate cylindrical continuouspassageway 42 extending the full length of the tube. The right endportion of tube 40 projects through the housing 18 of developmentstation 16 so that used toner received in the passageway 42 can bereturned to the sump of the development station for reuse.

A container 44 receives particles of used toner from the cleaningstation that are not to be recirculated through the development station.The end portion of tube 40 opposite from the development station has anopening 46 that communicates with passageway 42. Container 44 isconnected to the tube 40 so that the open upper end of the container isin communication with the opening 46 to allow used toner to pass throughpassageway 42 and opening 46 into the container 44.

Tube 40 has another opening 48 at the top of an intermediate portion ofthe tube for receiving used toner from the lower end of tube 36. Thetube 36 is connected to opening 48 through a passage 50.

An auger 52 is located in passageway 42 of the tube 40 for moving tonerthrough the passageway. The auger is driven from a reversible motor 54that is coupled to a shaft 56. A drive pulley 58 is mounted on shaft 56drives a similar pulley 60 through a belt 62. Pulley 60, in turn, isconnected to the auger 52 by a coupling 64. Thus reversible motor 54 iseffective to drive the auger 52 in either first or second oppositedirections about its axis. When driven in one direction the auger movesused toner particles in passageway 42 to the right as viewed in FIG. 2to return them to the development station 16. When the auger is drivenin the opposite direction, toner particles are driven to the left wherethey are discharged through opening 46 into the container 44.

While the apparatus of the invention could be used for alternatelyproviding used toner of a single color either to the development station16 or to the container 44, it is especially desirable for use withelectrographic apparatus as described previously which uses twointerchangeable development stations to alternately apply either tonerof a single color, such as black, or a second single color, such as red,green, etc., to the photoconductor for developing latent images. Whentwo color toner particles are being applied from each of twointerchangeable development stations, it may, for example, be desirableto recycle or recirculate toner of one color, such as black, from thecleaning apparatus 22 back to the development station 16 for reuse, anddeliver toner particles of any other color to the container 44 fordisposal. This will prevent contamination of black toner in the blackdevelopment station. Alternately, black toner could be delivered tocontainer 44 and toner of another color could be recycled to the sump ofa development station.

Control means for assuring recirculation of toner particles of one colorand collection of toner particles of other colors in the container 44can take various forms. For example, as shown in FIG. 2 of the drawings,two switches SW1 and SW2 can be provided for controlling motor 54. Whenswitch SW1 is closed the motor 54 rotates auger 52 in a direction todrive used toner particles into the station 16. On the other hand, whenswitch SW2 is closed the motor 54 rotates the auger 52 in the oppositedirection for delivering used toner particles to container 44.

The switches could be manually actuated by the operator each time thedevelopment station is changed, however it is preferred to close theswitches automatically and thus avoid a possible operator error whichcould lead to contamination. The switches can be automatically closed asa function of loading a development station into the electrographicapparatus. For example, one of the switches can be closed by connectionof a plug and socket for making the required electrical connectionsbetween a development station and the other electrographic apparatus.Also the switches can be closed by sensing a code notch or other inditiaon the development station 16 or the cartridge 20 for supplying freshtoner to the station. Such sensing can automatically determine the colorof the toner prticles in the development station. The switches SW1 andSW2 can be connected directly to the motor 54 as shown in FIG. 2, or canprovide a signal to the logic and control unit of the associatedelectrographic copier/duplicator which, through the associated software,will operate the motor to turn the auger in the desired direction.

By using the logic and control unit to control motor 54, anotherdesirable mode of operation is possible. Thus when a first developmentstation is replaced with a second development station having tonerparticles of a different color, the logic and control unit can switchthe motor to drive the auger in a direction to feed recovered tonerparticles to container 44 until a specific number of copies (e.g. fiftycopies) have been made with the toner in the second development station.Then the logic and control unit can reverse the direction of rotation ofthe motor and auger to feed recovered toner back to the seconddevelopment station. The number of copies made before reversing themotor should be sufficient to purge from the photoconductor and cleaningsystem substantially all toner particles from the first developmentstation.

While the invention has been described in detail with particularreference to a preferred embodiment thereof, it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

I claim:
 1. In electrographic apparatus having a photoconductor on whichlatent images can be formed, first and second interchangeabledevelopment stations for providing particles of toner of first andsecond colors to the photoconductor for developing the latent images, acleaning station for removing residual particles of used toner from thephotoconductor, the improvement comprises:a container for receivingparticles of used toner from the cleaning station, a tube having a firstend portion connected to the development station and a second endportion connected to the container, means for providing used tonerparticles from the cleaning station to an intermediate portion of thetube, an auger in the tube for moving toner through the tube, drivemeans coupled to the auger (1) for rotating the auger in a firstdirection for returning used toner particles to the development stationand (2) for rotating the auger in a second direction for feeding usedtoner particles to the container, and control means responsive to thepresense of the first development station to operate the drive means torotate the auger in its first direction, and the control means beingresponsive to the presence of the second development station to operatethe drive means to rotate the auger in its second direction.
 2. Inelectrographic apparatus having a photoconductor on which a latent imagecan be formed, interchangeable development stations for providingparticles of toner of a first color and a second color to thephotoconductor for developing the latent image, a cleaning station forremoving residual particles of used toner from the photoconductor, theimprovement comprises:a container for receiving particles of used tonerfrom the cleaning station, a tube having a first end portion connectedto the development station and a second end portion connected to thecontainer, means for providing used toner particles from the cleaningstation to an intermediate portion of the tube, an auger in the tube formoving toner through the tube, and drive means coupled to the auger (1)for rotating the auger in a first direction for returning used tonerparticles to the development station and (2) for rotating the auger in asecond direction for feeding used toner particles to the container, andcontrol means for the drive means, the control means comprising meansfor determining if toner particles of the first color or the secondcolor are being used to develop latent images, and the control meansbeing effective to operate the drive means to rotate the auger in itsfirst direction when toner particles of the first color are being usedto develop images, and the control means being effective to operate thedrive means to rotate the auger in its second direction when tonerparticles of the second color are being used to develop images.